Apparatus for covering a metallic core with a cast layer of another metal



March 6, 1951 APPARATUS FOR Filed Sept. 22. 1947 J L. REYNOLDS COVERINGA METALLIC CORE WITH A CAST LAYER 0F ANOTHER METAL 2 Sheets-Sheet 1(fig: f,

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March 6, 195] J. L. REYNOLDS 2,543,936

APPARATUS FOR COVERING A METALLIC CORE WITH A CAST LAYER 0F ANOTHERMETAL Filed Sept. 22, 1947 2 Sheets-Sheet 2 azm/lm g memo /6 #arm; MDormmmw Maw/m *9 4 l "I I l I 61 L ,1 I TQM/ w A Q avwowkw Patented Mar.6, 1951 APPARATUS FOR COVERING A METALLIC CORE WITH A CAST LAYER OFANOTHER METAL Julian L. Reynolds, Richmond, Va. Application September22, 1947, Serial No. 775,469 1 Claim. (01. 22-572) This inventionrelates to an improvement in an apparatus for fabricating metal, andmore particularly, to an apparatus for covering a metallic core with acast layer of anothermetal to produce a composite metallic wire, rod orbar in which the covering layer tenaciously adheres to the core and issmooth and uniform and of controlled thickness.

The present invention finds its major utility in the covering ofmetallic. cores with aluminum or aluminum alloys. It will bespecifically described in connection with the covering of cores offerrous metal with aluminum or its alloys although it is applicable toother dissimilar metals so long as the metal of the core has a melting pint substantially above that of the covering metal. Certain of theprinciples of the present invention are also applicable to the coveringof a metallic core having a melting point in the same range as thecovering metal, the details of the latter process being disclosed in mycopending application, Serial No. 778,777 filed October 9, 1947. In thepresent specification and claims, the term, "iron will be employed asgeneric to iron and its alloys including steel and the term aluminumwill be employed as generic to aluminum and its alloys except where thecontext shows the contrary to be intended.

Composite structures having an iron core and an aluminum covering areparticularly suitable for conductors of electrical currents, forexample, for power lines. Aluminum of conductor grade has highelectrical conductivity relative to its weight, but in general, has lowtensile strength. Composite wires or rods in accordance with the presentinvention can be produced so as to have high tensile strength byemploying a core of iron or other high tensile strength metal. At thesame time, the composite structure may have high electrical conductivitysince the covering of aluminum or other highly conductive metal may haveany desired thickness relative to the core. In addition to impartinghigh conductivity to the structure, the sheath of cast metal completelycovers the core and protects it from corrosion.

Previous attempts to cover ferrous metal or other cores with aluminumhave involved passing the core through a bath of molten aluminum andwithdrawing the core from the surface of the bath or spraying moltenaluminum on the core. By such procedures, the aluminum coating has beenrestricted to a thin layer not greater than a few thousandths of an inchin thickness and an attempt to increase this thickness has resulted inuneven or lumpy coatings. Even the thin coatings obtained are likely tobe uneven z 7 and, in some instances. discontinuous. Compositeconductors have, therefore, been usually fabricated by laying strands ofaluminum around an iron core, this construction being expensive andfailing to protect the core from corrosion.

The present invention enables a continuous covering sheath to be formedaround an iron core in a manner which welds the aluminum to the core.Furthermore. the covering sheath may be of substantially any desiredthickness, the core is accurately centered and the sheath is uniform inthickness and has a smooth outer surface. This is accomplished bypulling the core through a casting die while delivering molten metal tothe entrance end of the die. The entrance end of the die is maintainedat a temperature above the melting point of the covering metal and theremainder of the die is cooled. The molten metal is thereby formed intoa sheath and solidified in the die so that a continuous compositestructure having a solid metallic sheath welded around a metallic coreis obtained.

The successful application oi a sheath of aluminum welded to a core,particularly an iron core, requires that the surface of the coreentering the casting operation be exceptionally clean and free fromoxides and moisture. The invention, therefore, also contemplatescleaning and conditioning steps for the core. In some instances, it isdesirable to surface treat the core in order to provide an etched orpitted surface thereon for increasing the bond between the aluminum andthe core. In most cases, fluxes are not necessary or desirable, as theytend to contaminate the aluminum or other metal being cast, but in someinstances fluxes such as borax or boric acid are advantageously appliedto the core entering the casting operation. In general, the core shouldbe rigorously maintained out of contact with the atmosphere, or even besubjected to a reducing gas between the cleaning operation and thecasting operation. In general, cores of iron or other metal having amelting point substantially higher than the melting point of the metalbeing cast should be preheated to a temperature in the same range as themelting point of the covering metal before being introduced into thecasting die and the temperature of the molten metal entering the castingdie should be just above the melting point of such metal.

For producing composite wire of small diameter, it is frequentlydesirable to repeatedly draw the original composite bar through reducingdies. The metal of the core as well as that of the sheath is workhardened by drawing and it is usually necessary to anneal between atleast some of the auaosc drawing operations. Particularly in the case ofan iron core and an aluminum sheath, the annealing temperature of thecore is usually above the melting temperature of the sheath. Byemploying low temperature annealing ferrous alloys for thecore or highmelting point aluminum alloys, the annealing temperature of the core canbe brought below the melting temperature of the sheath to enableannealing of the entire structure. In this case annealing of the corealso takes place in the casting operation to condition the structure forsubsequent drawing.

It is therefore an object of the invention to provide an improvedapparatus for continuously casting a sheath of metal around a dissimilarmetal core to produce a composite wire, rod or Another object of theinvention is to provide an improved apparatus for casting a continuoussheath of metal around a core of dissimilar metal to produce acontinuous sheath completely covering the core and welded to the coreand of any desired thickness.

Another ob ect of the invention is to provide an' improved apparatus forcasting a metal sheath around a core of dissimilar metal in which thecore is pretreated to provide a firm and tenacious bond between the twometals.

Another object of the invention is to provide an improved apparatus forcasting a sheath of aluminum about a core of ferrous metal or other.metal having a substantially higher melting point than the aluminum.

Another object of the invention is to provide an improved apparatus forcasting a thick sheath of aluminum about a core of dissimilar metalhaving a substantially higher melting point than said aluminum toproduce a composite structure which can be drawn'to smaller size withoutrupturing the bond between the aluminum and the metal of the core.

A further object of the invention is to provide an improved apparatusfor producing a composite wire, rod or bar having a metallic sheath castabout a metallic core of a higher melting point metal than the metal ofthe sheath in which the metal of the core as well as that of the sheathmay be annealed.

Further objects and advantages of the invention will appear in thefollowingdescrlption of the preferred embodiments thereof given inconnection with' the attached drawings, of which:

Fig. 1 is a diagrammatic vertical section through a continuous sheathcasting apparatus:

Fig. 2 is a cross-section taken on the line 2-2 of Fig. 1;

Fig. 3 is a view similar to Fig. 1 showing modification of the castingapparatus;

Fig. 4 is a fragmentary view similar to Fig. 1 showing a furthermodification for casting a sheath about a plurality of strands forming acore;

Fig. 5 is a fragmentary end elevational view of a portion of theapparatus of Fig. 4;

Fig. 6 is a diagrammatic view similar to a flow sheet showing thepretreatment steps of the pr ss;

Fig. 7 is a view similar to Fig. 6 illustrating a modified process; and

Fig. 8 is another view similar to Fig. 6 illustrating a further modifiedprocess.

Referring to Fig. 1, the casting apparatus of the present inventionincludes a suitable container for molten metal, shown as a pot w, acasting chamber II, a casting die indicated generally at l2, pretreatlngapparatus indicated generally at I2. pulling apparatus shown as pullingrolls l4 and tension rolls I. The pot i0 is adapted to receive moltenmetal, such as molten aluminum from a ladle or other source. This potmay be provided with heat-insulation (not shown) or heating means (alsonot shown), as is well known in the art, to prevent solidification ofthe molten metal. The pot It may have a lower discharge opening I!communicating with a conduit is forming part of the casting chamberMolten metal flows downwardly by gravity from the pot into the castingchamber H and then into the entrance I! of the casting die I2.

The casting die l2 may include a casing 2| having a flange 22 forsecuring the casing 2| to the casting chamber ll and may have acylindrical lining 23 of refractory material. While a good grade of castiron is suitable for the pot l0 and casting chamber II, for most lowmelting point metals including aluminum, it has been found that thesolidifying aluminum or other metal welds to the walls of a metal die.The refractory material thus far found most satisfactory for aluminum isan extremely pure grade of graphite having a small crystal structure.The lining 23 has its outer surface accurately machined to fit theinterior of the casing 2| and has its inner bore 24 also accuratelymachined to substantially a true cylinder. In solidifying, the aluminumshrinks away from the walls of the die to provide clearance for thesolid bar or rod. The lining 23 may be replaceable and may be retainedin the casing 2| by a shoulder 26 at the entrance end of the casing 2|and an apertured disc 21, suitably secured to the discharge end of thecasing 2| and providing a shoulder also engaging the lining 23. Thecasting chamber H is preferably surrounded by suitable heating means,shown in Fig. 1 as being made up of electrical resistance units 28embedded in refractory 29. The heat input to the casting chamber IIshould be controllable so that the metal in the casting chamber may bemaintained accurately at a desired temperature, this temperature, ingeneral, being just slightly above the melting point of the metal beingcast. The core 30 may enter the casting chamber through a packing gland3| which aligns the core with the casting die. Accurately alignedtension rolls It may likewise operate in conjunction with the pull rollsll to hold the core in alignment with the casting die. In many cases, itis desirable to preheat the core entering the casting chamber II and anysuitable heating arrangement which will not cause corrosion of the coremay be employed. An induction heating coil 32, positioned in a closedchamber 33, has been shown. In general, it is desirable to maintain thecore 30 out of contact with the atmosphere after its surface has beenthoroughly cleaned. In order to accomplish this, the packing gland 3| isshown as being enclosed in chamber 34 into which an inert gas orreducing gas may be introduced through a pipe 36. This gas may then flowthrough the heating chamber 33 and into a closed chamber 31 surroundingtension roll l6.

The core 30 is then pulled through the casting die l2, the entrance endof which is preferably surrounded with molten metal in order to maintainthe entrance end of the die above the melting point of the metal beingcast. It is important that the molten metal entering the casting dieremain molten until it is well withanaeae I in the casting die, afterwhich it should be rapidly cooled to a solid state. In order to rapidlycool the molten metal, the major portion of the casting die ispreferably brought into direct contact with a cooling medium such aswater. Thus, the portion of the casting die exterior of the castingchamber ll may be surrounded by a casing 38 into which any suitableliquid cooling medium, for example, water may be introduced through apipe 39. The casing 38 may have a restricted discharge opening 4|concentric with the composite member issuing from the casting die sothat the casing 38 remains substantially full of liquid cooling medium,this COOIlIlg medium continuously entering through the pipe 39 and beingdischarged through the opening 4| in contact with the cast metal. Arelatively thick flange 22 on the casing 2| is preferably employed tominimize heat exchange between the heated entrance end of the casing andthe cooled discharge end. The casing 2| is preferably provided with aplurality of longitudinal slots 42, also shown in Fig. 2, which extendentirely through the casing so that the cooling medium comes into directcontact with the lining 23.

By pulling the composite bar 43 out of the casting die i2 at anappropriate speed, a smooth sheath of metal is continuously cast aroundthe core 30. The core is thus stretched between pull rolls I 4 andtension rolls [6 so that it is accurately positioned in the casting die,the packing gland 3i assisting in maintaining the position of the core30. It will be noted that the packing gland 3| has its inner memberdetachably secured to the casting chamber ii so that diiferent sized ordifferent shaped cores may be employed by merely substituting anappropriate packing gland. Furthermore, the external diameter of thesheath cast upon the core can be changed by merely substituting a lining23'having a difierent internal diameter. While the invention is chieflyconcerned with casting a circular sheath around a circular core, it isapparent that cores of any desired shape may be employed with a suitablepacking gland therefor and that the interior of the lining 23 of thecasting die may likewise have any desired shape.

As shown in Fig. 3, instead of employing a separate casting chamber, thecore may be pulled directly through a pot 44 having a packing gland 35secured to one side thereof and a casting die if secured to the otherside thereof. In this case, the molten metal in the lower portion of thepot 44 should be maintained at substantially the desired temperature forcasting, that is, a temperature just above the melting point of themetal. Since the casting die i2 is cooled, a supplemental heating means,such as electrical resistance elements 46, may be positioned adjacentthe entrance to the casting die in order to maintain the entrance to thecasting die surrounded by molten metal and to insure that the metalentering the casting die is in molten condition. Otherwise, theapparatus of Fig. 3 may be entirely the same as the apparatus of Figs. 1and 2.

The core entering the casting apparatus of Figs. 1 and 3 need not be asolid core. For example, it may be made up of a plurality of strandstwisted together. As shown in Fig. 4, it is entirelypossible to cast themolten metal around a plurality of parallel core elements 41. These coreelements may pass through tension rolls 48 individual to each of theelements and then through an aligning device 49 which may have aplurality of rolls 5i for aligning the various core elefor example,

ments with apertures 52 in a packing gland 53 having its inner elementsecured to a casting chamber such as the casting chamber I l of Fig. 1.A five-element core is shown in Figs. 4 and 5, but it is obvious thatany desired number of elements or strands may be employed for the core.Since the pulling apparatus, for example, the pulling rolls Id of Fig. 1and the tension rolls l6 maintain the core or core elements undertension in the casting chamber, even the strands of the multiple-strandcore of Figs. 4 and 5 are held in the desired position in the castingdie so that these core elements are accurately positioned in the finalcomposite bar.

- While the casting dies of Figs. 1 to 5 are shown as having horizontalaxes, it is possible to position a casting die so that it has a verticalaxis, with its entrance in the bottom of a pot for the molten metal.,With such an arrangement, the packing gland can be eliminated and asimple guide for the core substituted. Such a guide, however, shouldextend below the surface of the pool of molten metal so that the coreenters the pool below the surface of the molten metal, and is notcontaminated by contact with any film of oxides on the surface of thepool.

Fig. 6 illustrates a series of steps which can be employedin the presentinvention. In Fig. 6, the core 30 may be passed in succession through acleaning step 53, a drying step 56 and a heating and deoxidizing step 51prior to entering the casting chamber I l. The tension rolls 16 areshown as being positioned between the drying step 56 and the heatingstep 51 since, in general, the core can be passed in a straight linethrough the heating and deoxidizing step 51. It is, however, entirelypossible to position the tension rolls l6 directly in front of thecasting chamber ll, as shown in Fig. '7. The cleaning step of Fig. 6 maybe substantially any treatment which will remove substantiallyallforeign material from the surface of the wire. Such a cleaning stepusually involves passing the core through a cleaning solution whichsolution may be an alkali such as caustic soda or trisodium phosphate orit may be an acid solution such as sulfuric acid, hydrochloric acid,etc. The nature of the cleaning solution will depend upon the metal ofthe core as well as the type of impurities found on the core. Oilyforeign material generally requires an alkali cleaning while oxidizedmaterial frequently requires acid cleaning. A succession of stepsinvolving both acid and alkali cleaning operations are sometimesnecessary. The cleaning operatiton-may be entirely chemical orelectrochemical methods may be\e mployed, such as using the core as ananode in an electrolyte. If necessary, mechanical operations, such asbrushing or scrubbing, may likewise be employed and the cleaning stepmay be combined with a surface treatment step for giving an etched orpitted surface, as later discussed. Particularly in the case of an ironcore, a sodium hydride scale removing process where sodium hydride isthe essential ingredient in a molten composition, may be employed. Insome cases, it is desirable to leave a small amount of sodium hydride onthe core as a flux since this material assists in the bonding ofaluminum to iron wire. Other fluxes known to the art, such as borax orboric acid, may alternatively be employed after any of the cleaningoperations above discussed and may be applied to the core, for example,by dipping the core in a solution of the flux and then drying. I It is,however, desirable to avoid the use 7 of fluxes if a good bond can besecured in their absence, which is usually the case. It is importantthat the core be substantially free of moisture when it enters thecastin chamber. A drying step of any known or suitable type may beemployed, for example, subjecting the core to a stream of heated dryinggas which 1 is inert to or has a reducing action on the metal of thecore. Such a drying step may usually be combined with a preheating stepfor the core.

When treating cores having a melting point substantially higher than themelting point of the covering metal, best results are obtained bypreheating the core to a temperature approximately the same as that ofthe molten metal applied to the wire casting step before the core entersthe casting chamber. An efiective and simple manner of accomplishingthis preheating is by induction heat as indicated by the inductionheating coils 32 of Fig. l, but any other controllable heating operationmay be employed, such as exposing the core to the heat from electricresistance units, using the core itself as a resistance unit by flowingelectric current through the core, or passing the wire adjacent heatedrefractory surfaces. In general, it is necemary to avoid an oxidizingatmosphere, and best results are obtained by maintaining the core out ofcontact with the atmosphere from the time that it emerges from thecleaning step. A closed system containing an inert or reducing gas ispreferred.

Fig. 7 illustrates a somewhat more elaborate series of steps throughwhich the core may be passed aspiirt of the process for forming acomposite bar. In Fig. 7, a drawing Step 58 is indicated in advance ofthe cleaning step 54. The apparatus for such a drawing step may includea reducing die 59 and pull rolls 6!. In addition to accurately sizingthe core before it enters the casting operation, the drawing operationtends to remove or at least craze oxide coatings on the core to renderthe core more susceptible to cleaning in the cleaning step. Fig. '1 alsodiscloses a second drawing operation 62 having a reducing die 63 andpull rolls 64 after the casting operation to illustrate the fact thatthe composite structure issuing from the casting operation may bereduced in size by a drawing operation. In general, the compositestructure may be drastically drawn in one or a series of drawingoperations to reduce both the size of the core and the covering sheath.The sheath tenaciously adheres to the core, and by the method of Fig. 7,fine covered wires can be produced, particularly if the metals of thecomposite bar enable annealing of the core as well as the sheath, asdiscussed in more detail below.

Fig. 8 illustrates another series of steps which may be employedparticularly when the metal of the sheath is difllcult to weld to themetal of the core. The apparatus of Fig. 8 may involve a sur- 8clude\electroplating or the treatment of the core with a solution of ametal which is lower in the electromotive force series. 1 Fig. 8 alsoincludes a platingstep 61 which may follow the casting step. In such astep, any desired metal, such as copper o nickel, may be plated on tothe sheath by any known or suitable chemical or electroplatingstep. Ifthe plated metal is ductile, the'final composite bar may be drawn in adrawing step 62 to reduce the diameter of the structure.

The above-described cleaning operations, either with or without asurface treating step to produce a surface having minute pores or pits,enables the core to be introduced into the castin apparatus with asurface of virgin metal so that aluminum or other metal cast on the corewelds with or alloys with the surface of the core. As stated above, themolten metal is preferably maintained at a temperature just above itsmelting point. One reason for this is to reduce the amount of cooling ofthe casting die necessary to solidify the molten metal in the die. Inthe case of aluminum or the usual aluminum alloys having a melting pointrange from aproximately 1055" to 1220 F., the temperature of the moltenmetal may range from approximately 1100 F. to 1300 F. In some cases,where better welding of the covering metal to the core is obtained at ahigher temperature, temperatures substantially above the melting pointof the metal being cast may be employed in the casting chamber. Moltenaluminum has a tendency to rapidly dissolve certain metals includingsomegrades of iron or steel as well as copper, even though such metal has amelting point substantially above that of the aluminum. Such dissolvingaction weakens the core or may produce a relatively thick layer of analloy between the core and the sheath having undesirable properties.When such conditions are encountered, they may usually be corrected bydecreasing the temperature of preheat face treating step 66 positionedbetween the cleaning step 54 and the drying step 56, Such a surfacetreating step may include any operation which produces an etched orpitted surface on the core to provide a tooth" for bonding. Thetreatment may be a chemical or an electrochemical etching operation or amechanical treatment of the wire, such as scouring, wire brushing, sandblasting, grinding, or other abrading steps. The surface treating stepmay also involve a plating ste in which a metal which bonds well withaluminum or other metal being cast on a core is first plated on thecore. Such a plating step may inof the core or the length of time itremains in the molten metal or both. It may even be necessary to chillthe core before it enters the molten metal.

In many cases, the molten metal itself may be relied upon to preheat thecore before it enters the casting die and this is particularly true ofoperations such as illustrated in Fig. 3, where a considerable length ofthe core is exposed to the molten metal before the core enters thecasting die. It will be apparent that in Fig. l, casting chambers ofdifferent lengths may be employed in accordance with the nature of themetal of the core and of the metal being cast on the core so as toenable the core to be properly preheated by the molten metal. It isfurther apparent that the core may be partly preheated before it isintroduced into the casting chamber and then further preheated by themolten metal before the core enters the casting die.

When it is desired to pass the composite structure from the casting diethrough a series of drawing operations. the annealing of the core aswell as of the sheath between drawing operations becomes important. Inthe case of casting aluminum upon an iron core, the usual iron or steelcores have an annealing temperature substantially higher than themelting point of aluminum or aluminum alloys. Some drawing of the temperof the core can usually be obtained by employing temperatures below themelting point of the aluminum, but in general, a satisfactory annealingtreatment cannot be obtained. One way of fabricating a composite bar inwhich an iron core can be annealed is to employ a ferrous alloy Y 9which has a low annealing temperature. Such alloys are known to the artand examples of two suitable alloys are given below:

Such alloys anneal substantially below the melting point of aluminumwhich is approximately 1220 F. and below the melting point of mostaluminum alloys. With such a low temperature annealing iron core,aluminum of conductor grade can be successfully employed as a coveringmetal where the resulting composite structure is subjected to a seriesof drawing operations. An example of conductor grade aluminum is asfollows:

Per cent Aluminum 9955-983 Copper .05- .075 Silicon .04- .12 Iron .08-.24

The melting point of compositions in the above ranges varies fromapproximately 1210" to l220 F.

On the other hand, it is possible to employ standard iron or steel coreswhich anneal at temperatures substantially above 1220 F. Many metalswill increase the melting point of aluminum, among these metals beingiron, nickel, chromium, cobalt and tungsten. The proportions of thesevarious metals which may be added to aluminum may vary, but thefollowing percentages may be considered to be working examples:

Per cent Tungsten Iron s Nickel i5 Chromium 2 Cobalt 2 In theproportions given above, each of the metals individually added toaluminum will increase the melting point of the aluminum to atemperature substantially above the annealing temperature of most ironor steel having the requisite tensile strength, drawing properties,etc., suitable for cores of composite wires, rods or bars. It is, ofcourse, apparent that various combinations of the alloying metals listedmay be employed but care must be taken to avoid the formation ofeutectic mixtures having a lower melting point than desired.

In casting aluminum about a core, the core may be drawn continuously ata uniform rate through the casting die but in many cases, it has beenfound that superior results are obtained if the core is movedintermittently with rest'periods of short duration between periods ofmotion of the core. By such intermittent motion of the core through thedrawing die, more uniform may be employed. Many types of such pullingapparatus are known to the art. If pulling rolls are employed for thecasting operation, these rolls may be either rotated continuously orintermittently by any suitable driving apparatus. Also, tension rolls ithave been illustrated throughout the drawings, but it is also obviousthat any other known or suitable type of apparatus which resistsmovement of the core therethrough may be employed.

It will be apparent that the liquid molten metal at the entrance of thecasting die is under substantial pressure since the entrance end of thedie is a considerable distance below the upper surface of the moltenmetal. This pressure is ordinarily suflicient to cause the molten metalto flow evenly and uniformly into the entrance end of the casting die.It will be further apparent that the pressure at the entrance end of thecasting die may be increased, if necessary, in a particular castingoperation by increasing the height of the molten metal above the castingdie. This pressure may also be increased by applying pressure to thesurface of the body of molten metal, for example, by a pressure plungerpressing against the upper surface of the molten metal or by employing aclosed pot for the molten metal and maintaining a body of inert gasunder pressur above the molten metal. The process may be operatedintermittently, i. e., the pressure in the pot may be released while thepot is recharged with molten metal or the molten metal may becontinuously pumped into the pot. It is also possible to employ a pumpfor the molten metal beween the supply pot and the casting die, forexample, a gear or similar type of pump preferably constructed ofrefractory material or a refractory piston forcing molten metal into theen'- trance oi the casting die.

From the above disclosure, it is apparent that 4 I have provided asimple and rapidly operating apparatus for producing a composite wire,rod or bar by casting a metal sheath around a core. The resultingcomposite structure has the sheath tenaciously adhered or welded to thecore and the sheath is of uniform thickness with the core accuratelyplaced therein and has a smooth uniform surface. The covering sheath mayhave substantially any desired thickness. For example, the thickness ofthe sheath may range from a thousandth of an inch to a thickness severaltimes the diameter of the core. Large cores having thick sheaths may beemployed to produce wire or rods of small sizes including fine wire bysuccessive drawing operations upon the composite structure.

While I have disclosed the preferred embodiments of my invention, it isunderstood that the details thereof may be varied within the scope ofthe following claim. 4

I claim:

Apparatus for casting a metal sheath upon an elongated metal core havinga melting point substantially greater than that of the metal sheath,comprising an elongated horizontally disll posed casing divided into aseries of chambers by vertical walls centrally apertured to allow thecore to pass through the casing, tension rolls within the first chamberat the entrance end of the casing, core heating means disposed witha inthe second casing chamber, means for introducing a core protecting gasinto the third casing chamber, which gas emerges through the centralwall aperture into said second and first chambers while contacting saidcore, a casting chamber having an axial apertured gland extending intosaid third casing chamber and having an inlet for the introduction ofmolten sheath metal, heating means for said casting chamber. a castingmold having an entrance area projected into said casting chamber andhaving an exit area projected into a fifth casing chamber,

a slotted casing surrounding said exit area or the mold, means forcirculating a fluid cooling medium within said fifth casing chamber, andpull rolls acting in opposition to said tension rolls for advancing thecore through the casing chambers.

JULIAN L. REYNOLDS.

12 nnraaascas cn'an The following references are of record in the fileof this patent:

UNITED STATES PATENTS Number Name Date 310,994 Farmer Jan. 20. 1885443,536 Norman Dec. 30, 1890 910,674 Hancock Jan. 26. 1909 1,508,479Coats Aug. 5, 1924 1,706,130 Ruder Mar. 19, 1929 1,764,132 Wehr et al.June 17, 1930 2,055,980 Liebmann Sept. 29,-1936 2,072,060 Schultz Feb.23, 1937 2,091,588 Fiegel Aug. 31, 1937 2,136,394 Poland et a1. Nov. 15.1938 2,286,759 Patnode June 16, 1942 2,386,119 Jack Oct. 2, 19452,438,568

Mann Mar. 30, 1948

